Recent years have seen a rapid proliferation of small-sized electronic devices such as tablet computers and smartphones. In many cases, these electronic devices handle valuable information related to users owing to their convenience capable of being carried at all times and safety.
Given these circumstances, measures have been taken that improve security of electronic devices by setting passwords and authenticating users, for example. However, in password-dependent authentication, passwords may leak by human error or malicious attack. When a password leaks, even a person other than a user himself/herself can login using the password, and valuable data stored in an electronic device may be stolen.
Under the circumstances, in order to improve security, biometric authentication technologies are developed that determine whether an individual is authenticated using human biological information such as a fingerprint, a palm print, a vein pattern, an iris, a face, or a voice. Among such biometric authentication technologies, iris authentication can be ideal biometric authentication for such reasons as being low in error rate, being capable of authenticating at a remote position, and being stable with less change.
There is a technology as a conventional technology of small-sized electronic devices that have different through holes through which light passes between an irradiation unit and a light-receiving unit of infrared rays for a proximity sensor in order to avoid reception of light reflected by a surface of screen glass or the like. Conventional technologies are described in Japanese Laid-open Patent Publication No. 2013-178899.
However, recent years' small-sized electronic devices implement various functions, and the small-sized electronic devices mount many apparatuses for implementing the various functions. Given this situation, the small-sized electronic devices require that components are densely mounted for the pursuit of further miniaturization. Also when an iris authentication apparatus is mounted on the small-sized electronic devices, it is desirable that functions and performances of the iris authentication apparatus be implemented with a casing reduced in size without impairing convenience of users. Given these circumstances, the iris authentication apparatus is disposed in a confined area together with components for implementing a plurality of functions in line with users' demands.
The iris authentication apparatus includes two members, that is, an iris photographing camera and an iris illuminating light emitting diode (LED). Specifically, authentication is performed using an image acquired by illuminating an eye by the iris illuminating LED and receiving its reflected light by the iris photographing camera.
The iris authentication apparatus having such a structure can perform accurate authentication by appropriately aligning an angle of view of the iris photographing camera and an illumination angle of the iris illuminating LED. In order to widen a range in which accurate authentication can be performed, that is, an iris authentication space, it is desirable that an overlap between the angle of view of the iris photographing camera and the illumination angle of the iris illuminating LED be wider. However, when the angle of view of the iris photographing camera and the iris illuminating LED are excessively brought close to each other in order to maximize the iris authentication space, a red-eye phenomenon may occur, and an iris image may fail to be accurately extracted.
In contrast, when the distance between the iris photographing camera and the iris illuminating LED is separated as a measure for red eye, the illumination range of the iris illuminating LED is deviated, and the iris authentication space is reduced.
Given these circumstances, the iris illuminating LED may be angled in order to increase the iris authentication space while separating the distance between the iris photographing camera and the iris illuminating LED. As a measure therefor, a different flexible board from that for another adjacent apparatus may be used. However, when a plurality of flexible boards are used, it is difficult to ensure a mounting space within a small-sized electronic device.
Given these circumstances, the same flexible board as that for the other adjacent apparatus may be used. However, when an area adjacent to the close apparatus is only bent and angled, the iris illuminating LED protrudes upward from the surface of the small-sized electronic device and is difficult to be housed in the small-sized electronic device. Given this situation, in order to enable the iris illuminating LED to be housed in the small-sized electronic device, confined bending can be performed to form a step. Thus the iris illuminating LED can be disposed while being angled as illustrated in FIG. 16. FIG. 16 is a schematic diagram of an arrangement state when bending is performed to angle the iris illuminating LED. However, the components are excessively close to each other, thus making bent angles of bends 91 and 92 acute, increasing a repulsive force to the iris illuminating LED owing to relation among the thickness, the rigidity, and the bent angles of the flexible board, and making it difficult to fix the iris illuminating LED stably to the small-sized electronic device.